This application claims the benefit of Danish Application No. PA 2001 01106 filed Jul. 13, 2001, Danish Application No. PA 2001 01559 filed Oct. 24, 2001 and PCT/DK02/00487 filed Jul. 11, 2002.
The present invention concerns a method for in situ measuring of evaporation from a surface and an apparatus for measuring the evaporation from a surface. Curing technology concerns, among other things, adjustment and control of temperature and humidity conditions in hardening constructions and elements of concrete. The curing technology comprises further e.g. measurement/adjustment/control of moisture conditions in the early hardening phase of the concrete in order to achieve an optimal development of properties in the hardening concrete (“moisture curing”).
During the latest decades, the development within concrete technology has formed the basis of a new concept: High-Performance Concrete. Typically, a water/cement ratio (w/c ratio) in the range of 0.40–0.60 is used for conventional concrete, but today's superplasticizers have made it possible to manufacture relatively fluid concrete with a w/c ratio of 0.20–0.30 when up to 20% silica fume is added. With these extremely dense concretes, concrete strengths of 200–400 MPa can be achieved industrially, whereas in comparison, conventional concrete typically has concrete strengths of 30–50 MPa.
Danish concrete research has had a central role in the theoretical and experimental development of this new concept and several Danish companies are today involved in the industrial implementation of High-Performance Concrete in targeted special productions.
In curing technology terms the concept High-Performance Concrete means that the requirements for optimal and controlled moisture curing during hardening are significantly increased. At low w/c ratios, even modest losses of water in the early hardening phase may be detrimental to the subsequent hardening and property development of concrete.
In the field of High-Performance Concrete, it can be expected that the coming years will witness a growing need for simple, operational methods for the measurement/adjustment/control of the moisture curing conditions of concrete in the manufacturing process.